Transcript Session 5 Chen Ning_ENx

Operation &Control Technologies for
New Energy Power Generation and
Grid Integration
China Electric Power Research Institute
Sep. 21, 2013
Contents
1
Overview of New Energy Power Generation Development
2
Challenges to Grid Operation by New Energy Integration
3
Adaptive Requirement of the Grid to New Energy Integration
4
Key Operation & Control Technologies for New Energy Grid
Integration
5
Conclusion and Outlook
1. Overview of New Energy Power
Generation Development

Overview of Wind Power Development
In 2012, newly-increased global
installed capacity of wind power
单位：GW
Unit:
GW
was approximately 44GW, with a
year-on-year increase of less
than 20%, further experiencing a
slow-down in growth. It’s
basically in a development stage
with relatively flat growth. By the
end of 2012, the total global
installed capacity of wind power
reached 282GW.
Global newly- increased
installed capacity
Global accumulated installed
capacity
1. Overview of New Energy Power
Generation Development

Overview of Wind Power Development
China’s national installed
capacity of wind power
increased from 2540MW to
单位：GW
Unit:
GW
78.26GW in the past seven
years between 2006 and 2012,
which is far higher than global
average growth.
In 2012, on-grid wind energy
across the country amounted
to 100.8 billion kWh，
accounting for about 2% of
national power generation.
China newly-increased
installed capacity
China accumulated installed
capacity
1. Overview of New Energy Power
Generation Development

Overview of PV Power Development
In 2012, global newly-
Unit:
GW
单位：GW
increased PV installed
capacity hit a
new
historical high once again，
up to 34GW. Since then,
accumulated global PV
installed capacity totaled
102GW by the end of 2012.
Global newly-increased
installed capacity
Global accumulated installed
capacity
Annual growth rate
1. Overview of New Energy Power
Generation Development

Overview of PV Power Development
The year 2011 can be said as the
first year for
PV application in
单位：MW
Unit:
MW
China. Encouraged by a great deal of
policy, accumulated projects that are
under
construction
commenced
or
to
have exceeded
be
9GW
by the end of 2011; the formally
completed projects prior to December
30, 2011 have come up to 2.7GW. PV
market has been officially launched in
China. By the end of 2012, China’s
accumulated installed capacity has
reached 8.16GW.
China newly-increased
installed capacity
China accumulated installed
capacity
Contents
1
Introduction to New Energy Power Generation Development
2
Challenges to Grid Operation by New Energy Integration
3
Adaptive Requirement of the Grid to New Energy Integration
4
Key Operation & Control Technologies for New Energy Grid Integration
5
Summary and Outlook
2. Challenges to Grid Operation by New Energy
Integration
Peak
&
frequency
regulation
Reactive power
balance and
voltage level
Impacts of
new energy
on grid
Accomodation
ability
Stability
2. Challenges to Grid Operation by New Energy
Integration


Greater difficulty in system dispatch and peak regulation
Distinct anti-regulation properties of wind
Maximum: 27897.39
Time: 09-5-28 11:09:22
Minimum: 21710.12
Time: 09-5-28 03:59:41
power output, which renders difficulty in
system peak regulation.
24 hours
Load of Beijing-Tianjin-Tangshan Power Grid (MW)
Maximum: 386.60
Time: 09-5-28 02:26:06
Minimum:0.53
Time: 09-5-28 20:48:45
Wind power output and grid load
present higher anti-regulation
properties.
24 hours
Sum of wind power in Zhangjiakou Wind Power (MW)
2. Challenges to Grid Operation by New
Energy Integration

Greater difficulty in system dispatch and peak regulation
16000
Wind
power
Load
14000
Equivalent load
Wind power output (MW)
12000
功 率 (MW)
Power (MW)
Load (MW)
10000
光伏
电站出力
PV
output
Load
负荷
Equivalent
等 效 负 荷 load
8000
6000
4000
2000
Time (h)
0
10/20
10/21
10/22
10/23
10/24
Date
日期
10/25
10/26
Integration of wind and PV power results in greater fluctuation of equivalent load,
and thus bigger difficulty for grid dispatching.
10/27
2. Challenges to Grid Operation by New Energy
Integration

Greater difficulty in system dispatch and peak regulation
50.0Hz
49.8
50.2
Power generation
Regulatable power
generation output
Controllable
prime motor power
Power utilization
Conventional
Energy source
Grid
New energy
power
generation
Viable and non-controllable power for
new energy power generation, with low
prediction accuracy
Power load
Power load changes randomly
with higher
load prediction accuracy
2. Challenges to Grid Operation by New Energy
Integration
Greater difficulty in grid voltage control

In China, the areas where wind farms and PV power plants are grid integrated are mostly
at the end of the grid; substantial power changes makes it quite difficult to regulate grid
operation voltage, affecting the stability of system voltage.
235
As wind power output
increases rapidly, the
bus voltages of
Baicheng Grid and
Tongfa wind farm drops
to 213kV to the
minimum, with
substantial fluctuation.
230
225
kV

220
215
210
7:40
7:45
7:50
7:55
8:00
8:05
8:10
8:15
8:20
8:25
时间
220kVII bus voltage amplitude (ab) of Baicheng Substation
白城变220kVII母线电压幅值(ab)
220kVII main bus voltage amplitude (ab) of Zhenlai Substation
镇赉变220kV主母线电压幅值(ab)
同发风场220kV东母线电压幅值(ab)
220kVII eastern bus voltage amplitude (ab) of Tongfa Wind Farm
大安变220kV主母线电压幅值(ab)
220kVII main bus voltage amplitude (ab) of Daan Substation
220kVII
main bus voltage amplitude (ab) of Taonan Substation
洮南变220kV主母线电压幅值(ab)
长山电厂220kV北母线电压幅值(ab)
220kVII
northern bus voltage amplitude (ab) of Chagnshan Power Plant
2. Challenges to Grid Operation by New Energy
Integration

Proposing challenges to the integration capability of local grids

When wind farms and PV power plants are connected to the grid in a large-scale manner, the grid
will be faced with enlarged transmission flow during large-scale power generation and more heavyload operation lines, which makes thermal stability issue gradually prominent.
Due to limited capacity
for PV power generation
currently, such problem
is not conspicuous;
however, for wind power,
it’s relatively prominent.
2. Challenges to Grid Operation by New Energy
Integration

New energy power generation suffers poor anti-disturbance ability which affect the
safe operation of the grid.
 Large-scale new energy grid connection increases risks for stable operation of the grid.

Variable system flow, and difficult control over intertie operation;

Reduced system inertia and decreased dynamic stability ;

Failure to re-establish terminal voltage for new energy power plants after faults, causing
voltage instability;

As wind power units and PV power generation systems have no capability of LV ride through,
in the event of instaneous voltage drop induced by system disturbance, self trip will produce
impacts on the system.
Contents
1
Introduction to New Energy Power Generation Development
2
Challenges to Grid Operation by New Energy Integration
3
Adaptive Requirement of the Grid to New Energy Integration
4
Key Operation & Control Technologies for New Energy Grid Integration
5
Summary and Outlook
3. Adaptive Requirement of the Grid to
New Energy Integration

Technical Rule for Connecting Wind Farm to Power System GB/T 19963-2011

Active power control: all operating units in the wind farm should be capable of achieving continuous smooth
regulation on active power and of participating in active power control of the systems. Additionally, they should
be able to receive and execute the command to control active power and its changes assigned by dispatch
agencies. The recommended values ​for the change rate of the maximum power of the wind farm are given in
the following table.

Installed capacity of
wind farm（MW）
Maximum limit of changes to active
power in 10min（MW）
Maximum limit of changes to active
power in 1min（MW）
<30
10
3
30～150
Installed capacity /3
Installed capacity /10
>150
50
15
Reactive power control: wind turbine units in the wind farm should keep the power factor dynamically
regulatable in the range of between 0.95 leading or lagging. Specific configuration principles are proposed
for reactive capacity of the wind farm. The wind farm should be equipped with reactive voltage control
systems and be capable of reactive power regulation and voltage control.
3Adaptive Requirement of the Grid to New
Energy Integration

Technical Requirements for Connecting Photovoltaic power plant to Power
System GB/T 19964-2012

Active power control: Medium and large PV power plants should be equipped with active power control
systems and be capable of active power regulation. Besides, they should be able to receive and execute
automatically the command to control active power and its changes assigned by dispatch agencies of the
power systems. The recommended values ​for change rate of maximum power of the PV power plants are
given in the table below.
Installed capacity of
PV power plants
（MW）
Maximum limit of changes to active
power in 10min（MW）
Maximum limit of changes to active
power in 1min（MW）
Small
Installed capacity
0.2
Medium
Installed capacity
Installed capacity /5
Large
Installed capacity /3
Installed capacity /10
Note: Reduced output power of PV power plants caused by solar irradiance is beyond limitations
above.
3. Adaptive Requirement of the Grid to New
Energy Integration

Technical Requirements for Connecting Photovoltaic power plant to Power
System GB/T 19964-2012

Medium and large PV power plants should be equipped with reactive voltage control
systems and be capable of controlling reactive power and voltage. Specific configuration
principles are proposed for reactive capacity of medium and large PV power plants
connected to public grids via private lines and collections systems.

Small PV power plants can be of no capability of regulating reactive power and voltage.
When their output active power is 50% higher than their rated power, their power factor
should be no less than 0.98 (leading or lagging); while if their output active power is
20~50% higher than that of their rated power, their power factor should be no less than 0.95
(leading or lagging).
Contents
1
Introduction to New Energy Power Generation Development
2
Challenges on Grid Operation Generated by New Energy Access
3
Adaptive Requirement of the Grid to New Energy Integration
4
Key Operation & Control Technologies for New Energy Grid Integration
5
Summary and Outlook
4. Key Operation & Control Technologies for New
Energy Grid Integration

Objectives of new energy power generation control
 Satisfy the requirements of relevant standards on adaptability of grid for new energy power station

Change the extensive control mode of active / reactive power of new energy power plants
 Improve the control accuracy and rationality of active / reactive power of new energy power plants
 Enhance power quality of new energy power plants and avoid possibly trip
4. Key Operation & Control Technologies for New
Energy Grid Integration


Active power control related to new energy power generation
Control architecture

New energy power plant group
Scheduling division
调度部门
Active commands
有功指令
control

New energy power plant control

Active control of generation units
Master control station of
新能源电站群控制主站
new
energy power plant
group
Control substation of
新能源电站控制子站
new
energy power plant
Execution station of
新能源电站执行站
new
energy power
plant
Execution
执行单元
unit
Execution
执行单元
unit
Control substation of
新能源电站控制子站
new
energy power plant
Execution station of
新能源电站执行站
new
energy power
plant
Execution
执行单元
unit
Execution
执行单元
unit
Execution station of
新能源电站执行站
new
energy power
plant
Execution
执行单元
unit
Execution
执行单元
unit
Execution station of
new
energy power
新能源电站执行站
plant
Execution
执行单元
unit
Execution
执行单元
unit
4. Key Operation & Control Technologies for
New Energy Grid Integration


Reactive power control related to new energy power
generation
Control architecture

Reactive voltage control of regional grids

Reactive control of new energy power
Scheduling voltage
调度电压
Plan curve
计划曲线
plant group

Reactive control of new energy power
plant

Master AVC station of
区域电网AVC主站
regional power grid
Reactive control of generation units and
dynamic reactive compensation devices
Master AVC station of
新能源电站群AVC子站
new energy power plant
group
group
Reactive control of
新能源电站无功控制
new energy power
plant
执行
单元
Execution
unit
执行
单元
Execution
unit
Master AVC station of
新能源电站群AVC子站
new energy power plant
SVC
Reactive control of
新能源电站无功控制
new energy power
plant
执行
单元
Execution
unit
执行
单元
Execution
unit
SVC
Reactive control of
新能源电站无功控制
new energy power
plant
执行
单元
Execution
unit
执行
单元
Execution
unit
SVC
Reactive control of
新能源电站无功控制
new energy power
plant
执行
单元
Execution
unit
执行
单元
Execution
unit
SVC
4. Key Operation & Control Technologies for New
Energy Grid Integration


New energy power plant group control
Master control station

Communications: realize seamless integration of forecast data, dispatch commands and management
commands through construction of standardized interfaces;

Configuration: practise integrated control of active frequency, reactive voltage, and safe and stable
control;

Function: calculate optimal control capacity and control command with information received.
控制主站
Master control station
Wind-solar
风光联合
combined
power
forecast
功率预测
&prediction
system
预报系统
Prediction
Constraints
约束条件
预测信息
information
Data
数据
有功、无功控制平台
安稳控制系统
Active and reactive control platforms
Data
数据
control
控制命令
commands
计划曲线
Plan curve
Power
电力调度
dispatching
系统
system
运行方式优化
与电量计算
Data
数据
Data
数据
Operation optimization
and electric quantity
calculation
在线预警和辅助决策
Online warning and assistant decisionmaking
Data
数据
Data
数据
数据
Data
实时监测网络与数据支撑平台
Real-time monitoring on network and data support platform
电站控制
系统
Power plant
control system
Stabilization and
control system
4. Key Operation & Control Technologies for
New Energy Grid Integration

New energy power plant group control

Substation control

Communications: receive control capacity / control command and upload operating status information of the new
energy power plants / generation units;
Configuration: The control objects are main transformer tap of the booster station, reactive compensation devices,
wind farms, PV power plants; etc. ;
Function: the control commands of the master receiving stations regulate reactive compensation devices and the
main transformer taps as well as emergency cutting; they also function to decompose the control capacity
transmitted by the master station and send it to power plants.


子站控制系统
Substation
control system
补偿装置投切及调节
变压器分接头调节
Switch and regulate compensation devices
Transformer tap regulation
Forward control capacity or
转发控制容量或控制命令
control commands
Switch control of grid-connected
紧急情况下对场站并网点
points in farms/stations in case of
emergencies
进行开关控制
4. Key technologies on Grid-connected
Operation Control of New Energy


New energy power station group control
Execution station of new energy power plant

Communication: forward control command and upload operating status information of new energy power plants / generation
units ;

Configuration: Control objects are mainly reactive compensation devices, PV power generation units, wind turbine units, etc.;

Function: receive operating information of the monitoring systems in farms/stations and upload it to the control sub-station;
receive and execute control commands transmitted by control substations, and regulate PV power generation units as well as
switch and regulatie local compensation devices.
Monitoring
systems in
场站监控系统
farms/stations
Switch and regulate compensation
补偿装置投切与调节
devices
Forward control capacity
转发控制容量
Distribute
output of PV power
分配光伏发电单元出力
generation units
Cut紧急情况下对馈线进行切
control on feeder lines in case of
emergencies
除控制
4. Key technologies on Grid-connected
Operation Control of New Energy


Active power control of new energy power plant
Control principles

Satisfy the requirements for active control
performance indicators of new energy power plants
Scheduling
调度系统
system
Information
on
运行状态
operating
信息
status
Scheduling
by grid scheduling divisions

commands
调度指令
Based on the actual operation properties and power
Power plant
电站信息
information
Prediction
预测系统
system
Information
on
功率预测
power
信息
prediction
New energy
generation active control
新能源发电有功控制
forecast information of new energy power plants

Coordinate generation units with various regulation
performances

Control objectives

Track power generation plan commands issued grid
scheduling divisions

power generation benefits of new energy power
plants

Control objects

Wind turbine generator units

PV inverters
控制
Control
commands
指令
控制
Control
feedback
反馈
Generation
发电单元1
unit 1
控制
Control
commands
指令
控制
Control
feedback
反馈
Generation
发电单元n
unit n
4. Key technologies on Grid-connected
Operation Control of New Energy

Active power control of new energy power plant
 Control architecture
1. Limit mode: Active control system of new energy
power plants shall control the output of power plants
below preset limit or the limit issued by dispatching
agencies; the limit values can be given in different
time slots.
2. Difference mode: there’s power difference between the output
of new energy power plants and the forecasted power of wind
farms. Such power difference is pre-set value, or the value
issued by the dispatching agencies, which is equivalent to
reserving certain active power regulation margin for the stations.
4. Key technologies on Grid-connected
Operation Control of New Energy

Active power control of new energy power plant
 Control architecture
3. Slope mode: the changes of the output of new energy
power plants must be within the given slope in each control
cycle. The overall output power of the wind farms should
follow the given power of the power plants on condition that
the slope is satisfied.
4. Balance mode: under conditions of limited power change
rate, the active power control system of new energy plant
should immediately adjust its output to the power limit given by
grid dispatching agencies (if the given value is greater than the
maximum power, it can be adjusted to the maximum
generatable power) .
4. Key technologies on Grid-connected
Operation Control of New Energy


Reactive power control of new energy power plant
Control principles

Satisfy the requirements for reactive control
performance indicators of new energy power
plants raised by grid dispatching divisions

Based on actual operation properties and power
forecast information of new energy power plants

Comprehensive utilization of inverters, dynamic
reactive compensation and other reactive
sources

Consider coordination between static and
dynamic reactive controls

运行
Operating
information
信息
调度
Scheduling
commands
指令

Track voltage curves or reactive commands
issued by grid dispatching divisions

Improve energy quality of new energy power
plants
Power plant
电站信息
information
运行
Operating
information
信息
prediction
预测系统
system
Information
功率预测
on power
信息
prediction
新能源发电无功控制
New energy
generation reactive control
控制
Control
commands
指令
控制
Control
feedback
反馈
Current
transformer
变流器1…n
1…n
Control objectives
Booster
升压站
station
信息
information
Dispatching
调度系统
system
控制
Control
commands
指令
控制
Control
feedback
反馈
动态无功
补偿装置
Dynamic reactive
compensation
devices
控制
Control
commands
指令
控制
Control
feedback
反馈
Switchable
可投切
capacitance
电容、电抗
and reactance
4. Key technologies on Grid-connected
Operation Control of New Energy

Reactive power control of new energy power plant
 Control targets

Power generation unit AC devices
For new energy power generation units (such as double-fed wind turbine units, direct-drive wind
turbine units, PV inverters) that are connected with the grid through current transformers , in theory,
as long as the capacity of current transformers allows, the generation units themselves are capable
of providing reactive power; however, early asynchronous wind power generation units have no
such capability.

Reactive compensation devices
In accordance with national standards, to meet reactive demand of new energy power plants, all
the power plants should be equipped with corresponding reactive compensation devices. The
reactive compensation devices in use now are mainly two types, namely, SVCs (Static Var
Compensators) and SVGs (static synchronous compensators) .
4. Key technologies on Grid-connected
Operation Control of New Energy

Reactive power control of new energy power plant
 Control pattern
 Real-time voltage control pattern
Take voltage dispatching commands in real time from higher-level and control and maintain the
voltage of grid-connection points of new energy power plants around the command value.

Reactive power control pattern
It controls the power output of wind farms or PV power plants no more than the specified limit. The
limit value can be set.
 Power factor control pattern
Fixed deviation (limit) are always kept between PV output power and the maximum adjustable
output, which can be regarded as a means for PV power plants to participate in active reserve of
the system.
Contents
1
Introduction to New Energy Power Generation Development
2
Challenges on Grid Operation Generated by New Energy Access
3
Adaptive Requirement of the Grid to New Energy Integration
4
Key Operation & Control Technologies for New Energy Grid Integration
5
Conclusion and Outlook
5 Conclusion and Outlook

Conclusion
 Active power control of new energy power plant
In a long-term viewpoint, controllable operation of new energy power plants and integrate it into the
dispatching system of the grid is the development trend of safe grid-integrated development. Therefore, the
generation management of new energy power plants will become an important research direction in the field
of new energy grid-connection control. With improved technologies of active control related to new energy
generation, it will lead to enhanced new energy grid-connection capacity, better grid damping characteristics,
as well as continuously improved ability of new energy power plants to actively participate in grid regulation.
To improve the dispatching ability of new energy power generation and promote the operating mode of new
energy power plants to develop towards the way the conventional power plants does, will significantly
improve operating mode, power generation plans as well as security and stability of the power system of the
grids that accomodate large numbers of new energy power plants.
5 Conclusion and Outlook

Outlook
 Reactive power control of new energy power plant
Since new energy power plants are located at the end of the grid, substantial changes to the
output is bound to cause larger fluctuations in the grid voltage and thus affect the stabilization
of grid voltage; it will impose greater threats on secure and stable operation of the new energy
power plants themselves. Therefore, it’s a must to require new energy power plants to carry out
reactive voltage control which is also urgently needed for the development of new energy
plants themselves. One of the major pattern to develop new energy power generation in China
is to build up large new energy generation bases with centralized long- distance transmission.
Adopting a master and coordinated reactive voltage control strategy for new energy power
generation bases is a necessary way out for China’s new energy power generation.
End
Thanks
35